A lawyer in Tennessee who is mysteriously linked to millions of dollars in campaign contributions steered to congressional candidates doubled his investments in the weeks before Election Day and quietly funneled $6.8 million more to a prominent Tea Party group, according to new financial statements filed with the government.

William Rose of Knoxville previously said his business was a "family secret" and he was not obligated to disclose the origin of what now amounts to more than $12 million that he routed through two companies he recently created. Rose did not immediately return phone calls from the Associated Press on Friday.

The money went to the Tea Party's most prominent Super PAC, FreedomWorks for America, which spent it on high-profile congressional races. The $12 million accounted for most of the $20 million the group raised this year.

FreedomWorks did not respond to requests for an explanation, although CEO Matt Kibbe told Mother Jones magazine Friday, "I don't know about these (donations). It's the first time I've heard." The contributions are a glaring example of the murkiness surrounding who is giving money to politicians in modern elections, shaped by new federal rules allowing unlimited and anonymous donations. The law has allowed wealthy executives, corporations and other organizations to establish shell companies and mail drops to disguise the source of the money they give to political groups and politicians. But the mysterious donations linked to Rose by far eclipse any suspicious amounts paid to support the campaigns of President Obama and Republican Mitt Romney.

Rose made the latest $6.8 million in contributions even as the AP and Knoxville News Sentinel were jointly investigating $5.2 million in suspicious donations traced to one of the two companies during October. That company, Specialty Group Inc., filed incorporation papers in September, less than one week before it gave FreedomWorks several contributions worth $125,000 to $1.5 million each. Specialty Group appeared to have no website describing its products or services. It was registered to a suburban Knoxville home.